Method of making an insulated structure



Nov. 3, 1964 C. R. MORRIS METHOD OF MAKING AN INSULATED STRUCTURE Filed Nov. '7, 1960 WAKM H??? K} OVE'N RmsE coam/er 2 Sheets-Sheet l h l A wmzn I ave-N IN VEN TOR.

waif/720m Nov. 3, 1964 c. R. MORRIS METHOD OF MAKING AN INSULATED STRUCTURE 2 Sheets-Sheet 2 Filed NOV. 7, 1960 United States Patent 3,155,751 WTHUD OF MAKING AN INSULATED STRUCT Uarl R. Morris, Evansville, ind, assignor to Whirlpool Corporation, a corporation of Delaware Filed Nov. 7, 1960, Ser. No. 67,793 3 (Ilaims. (Cl. 264-45) This invention relates to cabinets and in particular to insulated cabinets such as for use in refrigerators.

In the conventional refrigerator cabinet, a mass of insulating material .is provided in the space between the inner liner and the outer wall defining the cabinet. Conventionally, such insulated cabinet structures have been provided by preforming the walls as separate panels with the insulating material previously installed therebetween, or by forcing the insulating material into the space between the liner and the outer wall as with pressurized air.

The present invention comprehends a new and improved method of making such an insulated cabinet in which the liner and outer wall are held in proper spaced relationship while a body of insulating material is foamed in place therebetween. Thus, a principal feature of the present invention is the provision of a new and improved method of making an insulated cabinet.

Another feature is the provision of such a method wherein inner and outer enclosures of the cabinet wall are held in a preselected spaced relationship while a body of insulating material is foamed in place therebetween.

A further feature of the invention is the provision of such a method comprising the steps of supporting a first enclosure having an open portion with the open portion uppermost, depositing in the lower portion of the enclosure a quantity of foamable material which reacts and sets to form an insulative body, disposing a second, smaller enclosure within the first enclosure with the walls of the enclosures in preselected spaced relationship, and retaining the enclosures in such relationship for a period of time permitting the material to foam and become set.

Still another feature of the invention is the provision of such a method wherein the enclosures are heated prior to the deposit of the foamable material.

'A yet further feature of the invention is the provision of such a method including the step of closing the space between the enclosures at the open portion of the first enclosure to contain the foamed material in the space.

Still another feature of the invention is the provision of such a method wherein the smaller enclosure is carried by a pair of gripping members urged outwardly into frictional retaining engagement with the inner side wall surfaces of the smaller enclosure.

Another feature of the invention is the provision of such a method including the step of directing a flow of liquid foamable material into the lower portion of the first enclosure to have a uniform distribution therein.

Other features and advantages will be apparent from the following description taken in connection with the accompanying drawings wherein:

FIGURE 1 is a perspective view of a refrigerator cabinet formed by a method embodying the invention.

FIGURE 2 is a schematic plan view of apparatus for practicing the method of the invention.

FIGURE 3 is a schematic elevation of the liner holding means, with the liner shown in diametric section, illustrating a first step in the method of the invention.

'FlGURE 4 is a View generally similar to that of FIG- URE 3 but illustrating a second step in the method of the invention.

FIGURE 5 is a schematic elevation, partially in section, of the outer cabinet wall disposed on a suitable conveyor.

FIGURE 6 is an enlarged fragmentary section showing the closure member, installed on the upper portion of the outer cabinet wall in greater detail.

FIGURE 7 is a schematic elevation illustrating the arrangement of the lin r on the carrying means within a suitable preheating apparatus.

FIGURE 8 is a schematic elevation showing the outer cabinet wall on the conveyor within a suitable preheating means.

FIGURE 9 is a schematic elevation illustrating the arrangement of the outer cabinet wall on the conveyor during delivery of the foamable material thereinto.

FIGURE 10 is a schematic elevation illustrating the arrangement of the liner and outer cabinet wall during the foaming and foam setting steps of the method.

In the exemplary embodiment of the invention as disclosed in the drawings, a refrigerator cabinet generally designated it) is provided with foamed-in place insulation 11 between an inner liner 12 and an outer wall member 13. An illustrative apparatus generally designated 14 for practicing the method of the invention is shown in FIG- URE 2. Briefly, the apparatus 14 may include a carrier device 15 for lifting and carrying the liner 12 firstly to a pre-heat oven 16 and thence to a space 17. The apparatus 14 further includes a conveyor 18 for carrying the cabinet outer wall member 13 to a pre-heat oven 19 and thence to adjacent a dispensing apparatus 20 for delivering foamab-le material .to within the cabinet. From apparatus Ztl, the cabinet is delivered to space 17 where it is raised by -a suitable platform structure 21 into a preselected spaced relationship with the liner -12 permitting the foaming material to till the space between the liner and cabinet wall member 33. The assembly of the liner, cabinet Wall and foam material is then delivered to a curing oven 22 wherein the foam material is rigidly set to complete the process.

As best seen in FIGURES 3 and 4, carrier device 15 is supported on an overhead rail 23 by a roller carriage 24. The roller carriage in turn carries a frame 25 from which pivotally depends a pair of outer arms 26 and a pair of inner arms 27'. The inner arms 27 are further provided with horizontal extensions 28 terminating outwardly in pads 29 for frictionally gripping the inner wall surface 39 of the liner 3.2 when the arms 27 are urged apart by suitable means such as pneumatic expansion device 31 extending between the lower ends of the arms 27. The liner is positioned for engagement by the pads 29 by elevating a table as, on which the liner is placed, by a suitable conventional hydraulic lift device 47. The liner is accurately positioned in the carrier device 15, as shown in FIGURE 4, by a plurality of guide blocks 32 carried on the frame 25 for engagement with the out/turned upper edge 33 of the liner when the liner is elevated by the lift device 47 into position for engagement by the pads 2d.

As shown in FIGURES 5 and 6, the outer cabinet wall member 13 is placed on a support 34 which rides on conveyor 18. The support 34 is provided with a plurality of links 35 arranged to engage pins 36 on the lower ends of arms 25 of the carrier device 15. The upper periphery of the outer wall member 13 is defined by an 3 inturned flange 37 on which is installed a silicone rubber closure member 38 extending the length of the flange 37. As shown, the closure member 38 is provided with a recess 48 in which the flange 37 is readily removably received for facilitated removal installation of the closure member on wall member 13.

Turning now to FIGURE 7, the rail 23 is seen to extend through the preheat oven 16, permitting the carrier device to be moved thereinto with the liner 12 carried thereby to be preheated to a temperature of approximately 120 F. As shown in FIGURE 8, the conveyor 18 is arranged to extend through the preheat oven 19, permitting the outer wall member 13 on support 34 to be moved into the oven 19 and be raised to a temperature of approximately 120 F. concurrently with warming of the liner.

Upon completion of the preheating operations, the outer wall member 13 is brought to a position underlying the nozzle 39 of the foamable material dispensing device 20. In dispensing the foambale material 40 onto the rear portion 41 of the cabinet wall 13, the device is manipulated to effect a uniform distribution of the foamable material thereon.

In the illustrated embodiment, the foamable material comprises a urethane foam material including as the ingredients thereof a polyester and/or polyether resin, toluene diisocyanate, a blowing agent such as Freon 11, Genetron 11, Isotron 11, or Ucon 11, a catalyst such as trimethylamine or triethylenediamine, and a surfactant such as the water soluble silicone derivative X-521 manufactured by the Union Carbide Company. The temperature of the mixed foam material 4-0 at nozzle 39 is preferably approximately 70 F.

As the material 40 begins to foam within approximately 40 seconds from the time it is delivered to within cabinet outer wall 13, it is necessary to move the cabinet wall 13 with the foam material therein quickly into position below the liner 12 carried on the carrier device 15 at space 17. This is effected, as shown in FIGURE 10, by placing the support 34 on a platform 4 which is elevated by suitable hydraulic means (not shown) to place the cabinet wall 13 in surrounding relationship with the liner 12. As the outer wall 13 moves upwardly, the distal ends 43 of the closure member 38 slides against the outer surface of the liner to have sealing engagement, at the final position thereof, with the outturned flange 33 of the liner thereby effectively closing the upper end of the hollow space 44 between the liner and outer wall. To assure an accurate spaced relationship betwen the liner and the outer wall, the outer wall is positioned on the support accurately by guides 45 thereon. The guides 45 are accurately positioned relative to the links 35 so that when the links 35 are brought into engagement with the pins 36 at the lower end of the arms 26 of the carrier device 15, the wall member 13 will be disposed accurately in the desired relationship with the liner 12. Further, the engagement of the links 35 with the pins 36 permits the platform 42 to be withdrawn from below the support 34 with the liner 12 and wall member 13 retained in the carrier device.

The foam material 40 now quickly foams in space 44 to completely fill the space up to the closure member 38. The preheating of the liner 12. and outer wall member 13 expedites the foaming process and assures the formation of a desirable hardened skin on the foam strongly adhering to the liner 12 and outer wall member 13.

The assembled liner and outer wall member are next delivered to the oven 22 wherein the foam is cured to form a rigid mass of thermal insulating material.

Upon completion of the curing operation, the completed cabinet structure 10 may be removed from the carrier device 15 by swinging the legs 26 outwardly and operating the device 31 to remove the pads 29 from association with the liner. Finally, the closure member 38 is removed from the cabinet 10 by stripping it upwardly therefrom. The non-adhesive characteristics of the silicone rubber material of which the closure member is formed precludes sticking of the closure member to the foam, thereby providing facilitated removal of the closure member.

Not only does the above disclosed method of forming cabinet structure 10 provide effectively maximum facility and low cost, but an improved uniform distribution of the foam insulation in the cabinet structure is obtained. More specifically, the disclosed method permits arrangement of material 40 on the rear wall portion 41 of the outer wall member 13 in a desirable uniform distribution eliminating the flow of the foam material over itself during the expansion thereof, thereby eliminating voids caused by a shearing action as results where the material is allowed to flow over itself. Further, the disclosed method permits the foam to expand substantially primarily in a vertical direction thereby effectively minimizing horizontal flow. Still further, the disclosed method effectively eliminates the delivery of the foamable material against material already partially expanded as occurs where the foamable material is delivered through a relatively small inlet at one portion of the space to be filled.

Having described my invention as related to the embodiment shown in the accompanying drawings, it is my intention that the invention be not limited by any of the details of description, unless otherwise specified, but rather be construed broadly within its spirit and scope as set out in the accompanying claims.

The embodiment of the invention in which an exclusive property or privilege is claimed is defined as follows:

1. The method of making an insulated cabinet, comprising the steps of: supporting a first enclosure having an open portion with the open portion uppermost; depositing in the lower portion of the enclosure a quantity of foamable material which expands and sets to form an insulative body; disposing a second, smaller enclosure within the first enclosure with the walls of the enclosures in preselected spaced relationship to provide an insulating space; closing the space between the enclosures at said open portion with a yieldable closure member; retaining the enclosures in such relationship for a period of time permitting the material to foam, expand into said space and become set against said closure member, said closure member being anti-adherent to said foam material; and removing said closure member after expansion of said material thereagainst.

2. The method of making an insulated cabinet, comprising the steps of: supporting a first enclosure having an open portion with the open portion uppermost; releasably securing a yieldable closure member to the first enclosure to extend inwardly partially across the open portion; depositing in the lower portion of the enclosure a quantity of foamable material which sets to form an insulative body; moving a second, smaller enclosure slidably against the closure member and into the first enclosure to have the walls of the enclosures in preselected spaced relationship and the closure member close the space between the enclosures at said open portion; retaining the enclosures in such relationship for a period of time permitting the material to foam against said closure member and become set, said closure member being antiadherent to said foam material; and removing the closure member from said set foam.

3. The method of making an insulated cabinet, comprising the steps of: supporting a first enclosure having an open portion with the open portion uppermost, depositing in the lower portion of the enclosure a quantity of foamable material; extending a pair of gripping members outwardly into frictional retaining engagement with the inner side wall surfaces of a second, smaller enclosure; moving the members to dispose the second enclosure within the first enclosure with the walls of the enclosures in preselected spaced relationship; retaining the enclosures in such relationship for a period of time permitting the material to foam and become set; releasing the gripping members from engagement with the second enclosure; and moving the gripping members from association with the enclosures.

References Cited in the file of this patent UNITED STATES PATENTS 1,632,957 Franke June 21, 1927 2,552,641 Morrison May 15, 1951 2,617,161 Oswald Nov. 11, 1952 2,639,252 Simon et a1. May 19, 1953 2,774,509 Knoblock Dec. 18, 1956 2,780,350

6 Alderfer Aug. 11, 1959 Miller Oct. 20, 1959 Risch Nov. 3, 1959 Rill et a1 Nov. 29, 1960 Olson et al Dec. 20, 1960 Thielen Sept. 19, 1961 Jorda et al. Aug. 21, 1962 Daniel Oct. 23, 1962 Kealing Feb. 19, 1963 OTHER REFERENCES Dupont Booklet, Rigid Urethane Foams; Methods of Application," June 1957, pp. 3-5.

Dupont Booklet, Rigid Urethane Foams, II, Chemistry Simon et a1. ,Feb, 5, 1957 15 and Formulation, HR-26, April 1958, pp. 41-44. 

1. THE METHOD OF MAKING AN INSULATED CABINET, COMPRISING THE STEPS OF: SUPPORTING A FIRST ENCLOSURE HAVING AN OPEN PORTION WITH THE OPEN PORTION UPPERMOST; DEPOSITING IN THE LOWER PORTION OF THE ENCLOSURE A QUANTITY OF FOAMABLE MATERIAL WHICH EXPANDS AND SETS TO FORM AN INSULATIVE BODY; DISPOSING A SECOND, SMALLER ENCLOSURE WITHIN THE FIRST ENCLOSURE WITH THE WALLS OF THE ENCLOSURES IN PRESELECTED SPACED RELATIONSHIP TO PROVIDE AN INSULATING SPACE; CLOSING THE SPACE BETWEEN THE ENCLOSURE AT SAID OPEN PORTION WITH A YIELDABLE CLOSURE MEMBER; RETAINING THE ENCLOSURES IN SUCH RELATIONSHIP FOR A PERIOD OF TIME PERMITTING THE MATERIAL TO FOAM, EXPAND INTO SAID SPACE AND BECOME SET AGAINST SAID CLOSURE MEMBER, SAID CLOSURMEMER BEING ANTI-ADHERENT TO SAID FOAM MATERIAL; AND REMOVING SAID CLOSURE MEMBER AFTER EXPANSION OF SAID MATERIAL THEREAGAINST. 